Method of handling a plastic container having a moveable base

ABSTRACT

Method for processing hot-filled plastic containers are provided. In some embodiments, the method may include hot-filling a plastic container, sealing the container, and conveying the sealed container, each with an inner annular wall and a push-up portion in a first position. In some embodiments, the method may further include creating a vacuum pressure in the hot-filled and sealed container and repositioning the push-up portion from the first position to a second position under a mechanical force.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional of U.S. patent application Ser.No. 15/074,791 (the '791 application), filed on Mar. 18, 2016 andpublished as US 2017/0197773.

The '791 application is a continuation of U.S. patent application Ser.No. 13/415,831 (the '831 application), filed on Mar. 8, 2012 andpublished as US 2013/0312368, now U.S. Pat. No. 9,731,884, issued Aug.15, 2017. The '831 application is a continuation-in-part of U.S. patentapplication Ser. No. 11/704,368 (the '368 application), filed on Feb. 9,2007 and published as US 2008/0047964, now U.S. Pat. No. 8,584,879,issued Nov. 19, 2013. The '831 application is also acontinuation-in-part of U.S. patent application Ser. No. 11/704,318 (the'318 application), filed on Feb. 9, 2007 and published as US2007/0199916, now abandoned.

The '831 application is also a continuation-in-part of U.S. patentapplication Ser. No. 13/412,572 (the '572 application), filed on Mar. 5,2012, now U.S. Pat. No. 9,145,223, issued Sep. 29, 2015. The '572application is a continuation of U.S. patent application Ser. No.11/704,338 (the '338 application), filed on Feb. 9, 2007 and publishedas US 2007/0199915, now U.S. Pat. No. 8,127,955, issued Mar. 6, 2012.

The contents and disclosures of each of the aforementioned applications,their publications and patents are incorporated herein by referencethereto.

In addition to the priority applications listed above, the followingpatents and patent applications also contain related disclosure and arefully incorporated herein by reference: U.S. patent application Ser. No.10/529,198, filed on Mar. 24, 2005, with a § 371 filing date of Dec. 15,2005, now U.S. Pat. No. 8,152,010, issued Apr. 10, 2012; InternationalApplication No. PCT/NZ2003/000220, filed on Sep. 30, 2003; New ZealandApplication Ser. No. 521694, filed on Sep. 30, 2002; U.S. patentapplication Ser. No. 10/851,083, filed on May 24, 2004, now U.S. Pat.No. 7,543,713, issued Jun. 9, 2009; U.S. application Ser. No.10/444,616, filed on May 23, 2003; U.S. patent application Ser. No.10/124,734, filed on Apr. 17, 2002, now U.S. Pat. No. 6,612,451, issuedSep. 2, 2003; U.S. Provisional Patent Application Ser. No. 60/284,795,filed on Apr. 19, 2001; U.S. patent application Ser. No. 10/363,400,entitled “Semi-Rigid Collapsible Container”, filed Feb. 26, 2003, nowU.S. Pat. No. 7,077,279, issued Jul. 18, 2006; International ApplicationNo. PCT/NZ01/00176, filed Aug. 29, 2001; New Zealand Patent ApplicationSerial No. 506684, filed on Aug. 31, 2000 and entitled, “Semi-RigidCollapsible Container”; New Zealand Patent Application Serial No.512423, filed on Jun. 15, 2001 and entitled, “Semi-Rigid CollapsibleContainer”; International Application No. PCT/US2004/024581, filed onJul. 30, 2004; U.S. Provisional Patent Application Ser. No. 60/551,771,filed Mar. 11, 2004; U.S. Provisional Patent Application Ser. No.60/491,179, filed Jul. 30, 2003; U.S. patent application Ser. No.11/413,124 filed Apr. 28, 2006, now U.S. Pat. No. 8,381,940, issued Feb.26, 2013; U.S. patent application Ser. No. 10/566,294, filed on Sep. 5,2006, now U.S. Pat. No. 7,726,106, issued Jun. 1, 2010; U.S. patentapplication Ser. No. 11/432,715, filed on May 12, 2006, now U.S. Pat.No. 7,717,282, issued May 18, 2010; U.S. patent application Ser. No.13/284,907, filed Oct. 30, 2011; and U.S. patent application Ser. No.11/413,583, filed Apr. 28, 2006, now U.S. Pat. No. 8,047,389, issuedNov. 1, 2011.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates generally to a hot-fill containerstructure that allows for the removal of vacuum pressure within thecontainer, and more particularly, to a hot-fill container structurehaving an invertible vacuum panel deeply set into the base of thecontainer. The present invention also relates to methods of making andprocessing containers having an invertible vacuum panel deeply set intothe base of the container.

2. Related Art

So called “hot-fill” containers are known in the art. Plasticcontainers, such as PET containers, are filled with various liquidcontents at an elevated temperature, typically around 185 degrees F.Once the liquid within the container cools, the volume of the containedliquid reduces, creating a vacuum within the container that pullsinwardly on the side and end walls of the container. This in turn leadsto deformation of the plastic container if it is not constructed rigidlyenough to resist the vacuum forces.

Typically, vacuum pressures have been accommodated by the use of vacuumpanels that deflect inwardly under vacuum pressure. Known vacuum panelsare typically located in the container sidewall and extend parallel tothe longitudinal axis of the container, and flex inwardly under vacuumpressure toward the longitudinal axis.

It is also known in the prior art to have a flexible base region toprovide additional vacuum compensation. All such known prior artcontainers, however, have substantially flat or inwardly recessed basesurfaces that deflect further inward to compensate for the vacuumforces. Known flexible base regions have not been able to adequatelycompensate for the vacuum forces on their own (i.e., vacuum panels inthe sidewall and/or or other reinforcing structures are still required).

Therefore, there remains a need in the art for plastic containers thatovercome the aforementioned shortcomings of the prior art.

BRIEF SUMMARY OF THE INVENTIONS

The present invention relates to a polymeric or plastic container havingan invertible pressure panel located in the container base. The pressurepanel is movable from an initial, outwardly-inclined position, to aninverted, inwardly-inclined position, in order to reduce the volume ofthe container and accommodate for vacuum forces within the container.The entire pressure panel is set deeply into the base of the container,such that no portion of the pressure panel extends beyond the standingring, regardless of whether the pressure panel is in the initialposition or the inverted position. This configuration can allow thecontainer to be supported by the standing ring regardless of whether thepressure panel is in the initial position or the inverted position.

Other plastic containers suitable for containing a liquid are disclosedin U.S. Pat. No. 5,261,544 issued to Weaver, Jr.; and U.S. Pat. No.5,908,128 issued to Krishnakumar et al.

As disclosed in Weaver, Col. 5, lines 26-29, a polymeric containershould be blow-molded with a minimum thickness of at least about 10mils.

As disclosed in Krishnakumar, Col. 4, lines 17-24, a container ofapproximately 20 ounces in volume made from ‘bottle grade’ PET (havingabout 1.5% comonomer and an intrinsic viscosity of about 0.80) may havea side-wall thickness on the order of 0.4 mm, or 15.7 mils, in order towithstand containing a heated liquid.

According to one exemplary embodiment, the present invention relates toa plastic container comprising an upper portion including a finishdefining an opening into the container, a lower portion including a basedefining a standing surface, a sidewall extending between the upperportion and the lower portion, the sidewall defining a longitudinalaxis, and at least one substantially transversely-oriented pressurepanel located in the lower portion. The pressure panel can be movablebetween an outwardly-inclined position and an inwardly-inclined positionto compensate for a change of pressure inside the container. Thestanding surface can define a standing plane, and the entire pressurepanel can be located between the standing plane and the upper portion ofthe container when the pressure panel is in the outwardly-inclinedposition.

According to another exemplary embodiment, the present invention relatesto a method of processing a plastic container, comprising the steps of(a) providing a plastic container having an upper portion including afinish, a sidewall, a lower portion including a base defining a standingsurface, and a substantially transversely-oriented pressure panellocated in the base; (b) introducing heated liquid contents into theplastic container with the pressure panel located in anoutwardly-inclined position entirely between the standing surface andthe upper portion; (c) capping the plastic container; and (d) moving thepressure panel to an inwardly-inclined position entirely between 30 thestanding surface and the upper portion.

According to yet another exemplary embodiment, the present inventionrelates to a method of blow molding a plastic container, comprising thesteps of (a) enclosing a softened polymer material within a blow molddefining a mold cavity, the blow mold comprising at least first andsecond side mold portions and a base mold portion; (b) inflating thepolymer material within the blow mold to at least partially conform thepolymer material to the blow mold cavity; and (c) displacing the basemold portion with respect to the first and second side mold portions toform a transverse pressure panel deeply set within a base portion of theplastic container.

Further objectives and advantages, as well as the structure and functionof preferred embodiments will become apparent from a consideration 10 ofthe description, drawings, and examples.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features and advantages of the invention will beapparent from the following, more particular description of a preferredembodiment of the invention, as illustrated in the accompanying drawingswherein like reference numbers generally indicate identical,functionally similar, and/or structurally similar elements.

FIG. 1 is a perspective view of an exemplary embodiment of a plasticcontainer according to the present invention, shown with a pressurepanel in an initial, outwardly-inclined position;

FIG. 2 is a side, sectional view of the plastic container of FIG. 1,shown with the pressure panel in the initial, outwardly-inclinedposition;

FIG. 3 is a side, sectional view of the plastic container of FIG. 1,shown with the pressure panel in an inverted, inwardly-inclinedposition;

FIG. 4 is a bottom view of the plastic container of FIG. 1;

FIG. 5 is a perspective view of another exemplary embodiment of aplastic container according to the present invention, shown with thepressure panel in the initial, outwardly-inclined position;

FIG. 6 is a bottom view of the plastic container of FIG. 5;

FIG. 7 is a perspective view of a portion of a plastic containeraccording to yet another exemplary embodiment of the present invention,shown with the pressure panel in an initial, outwardly-inclinedposition;

FIG. 8 is a bottom view of the plastic container of FIG. 7;

FIG. 9 is a side, sectional view of a portion of the plastic containerof FIG. 7, shown with the pressure panel in the initial,outwardly-inclined position;

FIG. 10 is a side, sectional view of a portion of the plastic containerof FIG. 7, shown with the pressure panel in the inverted,inwardly-inclined position;

FIGS. 11A-11E schematically illustrate an exemplary method of processinga plastic container according to the present invention;

FIGS. 12A-12C schematically illustrate an exemplary method of forming aplastic container according to the present invention;

FIG. 13 is a side view of a portion of a plastic container according toanother embodiment of the present invention;

FIG. 14 is a side, sectional view of the plastic container of FIG. 13,shown with the pressure panel in the initial, outwardly-inclinedposition;

FIG. 15 is a perspective view of the plastic container of FIG. 13, shownwith the pressure panel in the initial, outwardly-inclined position;

FIG. 16 is a side, sectional view of a portion of a plastic containeraccording to another embodiment of the present invention;

FIG. 17 is a perspective view of the plastic container of FIG. 16, shownwith the pressure panel in the initial, outwardly-inclined position;

FIG. 18 is a side, sectional view of a portion of a plastic containeraccording to another embodiment of the present invention;

FIG. 19 is a perspective view of the plastic container of FIG. 18, shownwith the pressure panel in the initial, outwardly-inclined position;

FIG. 20 is a schematic representation of a system for handling plasticcontainers;

FIG. 21 is a schematic representation of handling plastic containers;

FIG. 22 illustrates a lower portion of a container similar to that shownin FIG. 7 according to an alternate embodiment;

FIG. 23 illustrates a lower portion of the container of FIG. 13 similarto the view shown in FIG. 8 according to an alternate embodiment;

FIG. 24 is a bottom plan view of FIG. 8 with planes C-C and D-Dindicated;

FIG. 25 is a side section view of FIG. 15 taken along C-C;

FIG. 26 is a side section view of FIG. 15 taken along D-D;

FIG. 27A is a side view of the plastic container of FIG. 5;

FIGS. 27B and 27E are side sectional views of the plastic container ofFIG. 6 through plane B-B; and,

FIGS. 27C and 27D are side sectional views of the plastic container ofFIG. 6 through plane C-C.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the invention are discussed in detail below. Indescribing embodiments, specific terminology is employed for the sake ofclarity. However, the invention is not intended to be limited to thespecific terminology so selected. While specific exemplary embodimentsare discussed, it should be understood that this is done forillustration purposes only. A person skilled in the relevant art willrecognize that other components and configurations can be used withoutdeparting from the spirit and scope of the invention. All referencescited herein are incorporated by reference as if each had beenindividually incorporated.

As discussed above, to accommodate vacuum forces during cooling of theliquid contents within a hot-fill container, plastic containers havetypically included a series of vacuum panels located around the sidewalland/or in the base portion. The vacuum panels deform inwardly, and thebase deforms upwardly, under the influence of the vacuum forces. Thisconfiguration attempts to prevent unwanted distortion elsewhere in thecontainer. However, the container is still subjected to internal vacuumforces. The sidewalls and base merely provide a suitably resistantstructure against that force. Additionally, the vacuum panels in thesidewall can undesirably detract from the appearance and feel of thecontainer, and limit the design possibilities for the container.

Typically at a bottling plant, the containers are filled with a hotliquid and then capped before being subjected to a cold water spray,resulting in the formation of a vacuum within the container. Thecontainer structure needs to be able to cope with this vacuum force.U.S. patent application Ser. No. 10/529,198, filed on Dec. 15, 2005, theentire content of which is incorporated herein by reference, discloseshot-fill containers that provide for the substantial removal orsubstantial negation of the vacuum pressure within the containers. Thedisclosed containers include a transversely-oriented pressure panellocated in the container base. The pressure panel is movable between 10an initial, outwardly inclined position, and an inverted, inwardlyinclined position, in order to reduce the volume of the container andaccommodate for vacuum forces within the container. The presentinvention relates to additional embodiments of this concept in which thepressure panel is set deeply into the base of the container, such thatno portion of the pressure panel extends 15 beyond the standing ring,regardless of whether the pressure panel is in the initial position orin the inverted position. This configuration can allow the container tobe supported by the standing ring regardless of whether the pressurepanel is in the initial position or the inverted position.

Referring to FIGS. 1-4, an exemplary embodiment of a plastic container10 according to the present invention is shown. The container 10 caninclude an upper portion 12 including a finish 14 that defines anopening into the interior of the container 10. As shown, the finish 14can include threads 16 or other structures adapted to secure a closure(not shown) onto the container 10. The container 10 can also include alower portion 18 having a base 20, and a sidewall 22 extending betweenthe upper portion 12 and the lower portion 18. The base 20 can define astanding surface 21 that is substantially flat and adapted to supportthe container 10 in a substantially upright position (e.g., withlongitudinal axis A substantially perpendicular to the surface on whichcontainer 10 is resting).

In the exemplary embodiment shown, the sidewall 22 is substantiallytubular and has a substantially circular transverse cross-sectionalshape. Alternative cross-sectional shapes can include, for example, anoval transverse cross-section; a substantially square transversecross-section; other substantially polygonal transverse cross-sectionalshapes such as triangular, pentagonal, etc.; or combinations of curvedand arced shapes with linear shapes. As will be understood by one ofordinary skill in the art, when the container 10 has a substantiallypolygonal transverse cross-sectional shape, the corners of the polygonare typically rounded or chamfered. Although the container 10 is shownas having reinforcing ribs or rings 23 in the sidewall 22 to resistpaneling, dents and other unwanted deformation of the sidewall,particularly under vacuum force, other embodiments are possible wherethe sidewall 22 is substantially devoid of such features (e.g., thesidewall 22 can be smooth like that of a conventional glass container).

As best seen in FIG. 4, a portion of the base 20 can include a pluralityof reinforcing ribs 24, however other embodiments with or without thereinforcing ribs 24 are possible.

The lower portion 18 of the container 10, and particularly the base 20,can include a substantially transversely-oriented pressure panel 26. Thepressure panel 26 can be moved between an outwardly-inclined position(shown in FIGS. 1 and 2) and an inwardly-inclined position (shown inFIG. 3) in order to reduce the internal volume of the container 10 andcompensate for any vacuum forces created within the container, forexample, during the filling process. For example, the pressure panel 26may substantially remove the internal vacuum that develops within thecontainer 10 during a hot-fill process once the container 10 has beenhot-filled, capped, and cooled.

As best seen in the sectional views of FIGS. 2 and 3, the pressure panel26 can be deeply set into the container 10 in order to facilitatestanding of the container 10 on its standing surface 21 regardless ofwhether the pressure panel 26 is located in the outwardly-inclinedposition (FIG. 2) or the inwardly-inclined position (FIG. 3). In otherwords, the entire pressure panel 26 structure can be located between theplane P of the standing surface 21 and the upper portion 12 of thecontainer 10 when the pressure panel 26 is in the outwardly-inclinedposition (FIG. 2) and also when the pressure panel 26 is in theinwardly-inclined position (FIG. 3).

According to the exemplary embodiment shown in FIGS. 1-4, the lowerportion 18 of the container 10 includes a concave outer wall portion 30that extends from the lower end of the sidewall 22 to the standingsurface 21. The standing surface may be a ring or annular portion asshown in FIG. 1, or may be discontinuous as shown in FIG. 5. Thepressure panel 26 is deeply set into the lower portion 18 of thecontainer 10 via an inner wall 32 that extends from the standing surface21 to the pressure panel 26. The inner wall may therefore comprise aninstep or hollow recessed portion between the pressure panel 26 and thestanding surface 21. In the exemplary embodiment shown, the inner wall32 is parallel or nearly parallel to the longitudinal axis A of thecontainer 10, and provides the recessed portion with a concave annularring shape; however, other configurations and/or inclinations of theinner wall 32 are possible that are not concave annular ring structures,and may have different angles as shown in FIGS. 18-19 with reference tothe inner wall 1120. In addition, one of ordinary skill in the art willknow that other configurations besides the inner wall 32 may beimplemented to set the pressure panel 26 deeply into the lower portion18. An annular, recessed channel 34 can be provided in the inner wall 32adjacent the standing surface 21 to provide a further recessed concavering structure in the inner wall 32. In the exemplary embodiment shown,the annular recessed channel has a substantially square or annularcross-section, however, other shapes are possible for the channel to beinwardly stepped. Channel 34 can act as a rib member and reinforce thefoot portion or standing surface 21 and/or facilitate stacking ofmultiple containers on top of one another, depending on the shape andsize of the finish 14 and/or closure.

In the exemplary embodiment of FIGS. 1-4, the standing surface 21, innerwall 32, and outer wall 30 are substantially continuous about thecircumference of the container 10 (see FIG. 4). However, as shown in thealternative embodiment of FIGS. 5 and 6, and FIGS. 27A-27E, thecontainer 10′ can have a standing surface 2T, inner wall 32′, and outerwall 30′ that are discontinuous.

The pressure panel or inner annular wall 240 has an inner periphery 244and an outer periphery 242, and is set, with respect to the longitudinalaxis and the opening into the container, at an outward or downward angleprior to filling with a heated liquid. The outer annular wall includessupport or foot portions 230 and the inner wall potions 32′ extend fromthe standing surfaces 21′ to the inner annular wall or pressure panel240. Radial webs or straps 246 are uniformly spaced apart and separateeach support 230. The web surface is closer to the finish than thefooted contact surface, or expressed another way, the webs 246 arelongitudinally displaced above the footed contact surface 21′. Inaddition, each support 230 has a larger arcuate extent than that of eachradial web 246. The inner annular wall 240 extends within the concaveouter annular wall 30′. The outer periphery 242 of the inner annularwall or pressure panel 240 merges with the inner wall 32′ of each of thesupports 230, and with the plurality of spaced-apart, horizontallydisposed, radial webs or straps 246 located adjacent the outer periphery232 of the standing surface of the base. Each of the webs 246 extendsbetween the supports 230 and connects to the container sidewall 22 inthe lower portion 18 at an elevation above the horizontal plane “P”extending through the standing surface 21 to form radius 202 such thatweb surface 246 is visible from a side of the container. Preferably theinner annular wall 240 and the central dimple or push up 248 merge viaan annular hinge 250 at the foot of the push-up, comprising radius 251.

In order to facilitate movement (e.g., folding) of the pressure panel 26between the outwardly-inclined position of FIG. 2 and theinwardly-inclined position of FIG. 3, pressure panel 26 can include adecoupling or hinge structure 36 that is located between the inner wall32 and the pressure panel 26. In the exemplary embodiment shown, thehinge structure 36 comprises a substantially flat, non-ribbed region,that is susceptible to folding, however, other configurations of thehinge structure, such as a crease, are possible.

Referring now particularly to FIG. 4, the pressure panel 26 can comprisean initiator portion 40 and a control portion 42. Both the initiatorportion 40 and control portion 42 can comprise part of the pressurepanel 26 that folds when the pressure panel 26 is moved from its initialposition in FIG. 2 to its inverted position in FIG. 3. The initiatorportion 40 can be adapted to move or fold before the rest of thepressure panel 26 (e.g., before the control portion 42). In theexemplary embodiment shown, the control portion 42 is at a steeper angleto the standing plane P than the initiator portion 40, thereby resistingexpansion of the pressure panel from the inverted state (FIG. 3) to theinitial state (FIG. 2), for example, if the container 10 wereaccidentally dropped.

In order to maximize the amount of vacuum compensation from the pressurepanel 26, it is preferable for at least the control portion 42 to have asteep angle of inclination with respect to the standing plane P. Asshown in FIG. 2, the control portion 42 can be at a first angle alpha,with respect to the standing plane P. According to one exemplaryembodiment, the first angle alpha, can be at least 10 degrees, andpreferably is between about 30 degrees and about 45 degrees. Accordingto this embodiment, the initiator portion 1 can be at a second anglebeta, with respect to standing plane P, that is at least 10 degrees lessthan the first angle alpha.

When the pressure panel is inverted from the outward state (FIG. 2) tothe inward state (FIG. 3), it can undergo an angular change that isapproximately equal to its angle of inclination. For example, if thecontrol portion 42 is initially set at an angle alpha, of about 10degrees, it will provide an angular change of approximately 20 degrees.At such a low angle of inclination, however, it can be difficult toprovide an adequate amount of vacuum compensation in a hot-filledcontainer. Therefore it is preferable to provide the initiator portion40 and control portion 42 with steeper angles. For example, with thecontrol portion set at an angle alpha, of about 35 degrees, the pressurepanel 26 will undergo an angular change of about 70 degrees uponinversion. According to this exemplary embodiment, the initiator portion40 can be set at an angle beta, of about 20 degrees.

Referring to FIGS. 22-23, a base portion of a container according to analternative embodiment is shown, wherein the control portion of thepressure panel comprises a substantially continuous conical areaextending around the base. According to this embodiment, the initiatorportion 140 and the control portion 142 are set at a common angle, suchthat they form a substantially uniform pressure panel 126. However,initiator portion 140 may still be configured to provide the leastamount of resistance to inversion of pressure panel 126, such that itstill provides an initial area of folding or inversion. For example, theinitiator portion 140 may have a smaller material thickness than thecontrol portion 142. According to the embodiment shown in FIGS. 22-23,initiator portion 140 causes the pressure panel 126 to begin inversionat its region of widest diameter, near the hinge structure 136.

Additional structures may be added to the pressure panel 126 in order toadd further control over the inversion process. For example, thepressure panel 126 may be divided into fluted regions, as shown in FIGS.6 and 7. As shown, the fluted regions 145 can be outwardly convex,resulting in inward creases 127 between each outward flute and evenlydistributed around the container's longitudinal axis to createalternating regions of greater and lesser angular inclination. Referringto FIGS. 24-26 in particular, panel portions 145 that are convexoutwardly, and evenly distributed around the central axis create regionsof greater angular set 219 and regions of lesser angular set 218. Theangular set in the midline 218 of each of the plurality of flutes 145has lesser angular set gamma than the angular set delta in the pluralityof creases 218 created between each fluted panel portion 145. This mayprovide for greater control over the inversion of the panel. Suchgeometry provides increased resistance to reversion of the panel, and amore even distribution of forces when in the inverted position. Thistype of geometry can provide increased resistance against the panelreturning from the inward position (FIG. 10) to the outward position(FIG. 9), for example, if the container were dropped. The flutedconfiguration can also provide more even distribution offerees on thepressure panel 126. According to an alternative embodiment, the flutescan be inwardly concave. Inwardly directed flutes offer less resistanceto initial inverting forces, coupled with increased resistance toreverting back to the original, outward position. In his way, theybehave in much the same manner as ribs to prevent the panel being forcedback out of the outwardly inclined position, but allow for hingemovement from the first outwardly inclined position to the inwardlyinclined position. Such inwardly or outwardly directed flutes orprojections function as ribs to increase the force required to invertthe panel. Further details regarding the pressure panel and fluting aredisclosed in co-pending U.S. patent application Ser. No. 10/529,198,filed on Dec. 15, 2005, the entire content of which is incorporatedherein by reference.

FIGS. 13 to 15 show another exemplary embodiment of a container that canbe used as described herein. The container includes an upper portion1102, shoulder 1104, body 1106 and base 1108. The upper portion 1102includes an opening into the container which may be closed and sealed,such as via a screw cap using thread 1112.

The container body 1106 in the present example includes ribs 1114 in afirst region thereof and panels 1116 in second portions thereof. Panels1116 in this example act as vacuum panels as discussed below and alsofacilitate gripping of the container by a consumer, but in otherexamples may be configured to serve only as grip panels and not pressurepanels. In another example, vacuum panels may be placed in the containerbody separately from the grips or without the grips.

The container base 1108 includes standing ring or bearing surface 1118on which the container rests when in an upright position. Adjacent thestanding ring 1118 is a recess or instep forming a first wall 1120 whichjoins pressure panel or second wall 1124 via a hinge structure 1122. Aninwardly projecting push-up or section 1126 is provided in the center ofthe base 1108. The panel or second wall 1124 may include creases 1128 asshown which aid control over the configuration of the panel or secondwall 1124 as it moves between outwardly and inwardly inclined positions.

The container of FIGS. 13 to 15 is particularly adapted to hot-fillapplications but may be used in other applications where there arechanges in pressure inside the container.

According to one hot-filling method using the container of FIGS. 13-15,the container is provided to a filling station with the second wall 1124configured as shown in FIGS. 14 and 15. The container is then filledwith hot or heated liquid and sealed, for example, using a screw cap. Asthe container cools, contents of the container (particularly theheadspace), contract. This causes the pressure in the container to drop.Cooling may be accelerated, for example, by spraying the outside of thecontainer with water.

To prevent unwanted deformation of the container caused by the reductionin internal pressure, one or both pressure panels 1116, 1124 areconfigured to move inwards to reduce the container volume and increasethe internal pressure of the container. In one example, at least thepanels 1116 provided in the container sidewall are adapted to moveinwards through action of the vacuum force generated inside thecontainer during cooling, and in another example the panel 1124 isadapted to move inward through action of the vacuum force generatedinside the container during cooling. In a third example, both moveinward, and in a further example, the container sidewalls are subjectedto vacuum force prior to the base.

In the present example, panel 1124 is also configured to move to adjustthe container volume. More particularly, panel 1124 is configured toinvert about hinge structure 1122 from being outwardly inclined as shownin FIGS. 14 and 15 to being inwardly inclined (not shown).

Inversion of the panel 1124 may be initiated by engagement of a pusheror other external mechanical force against the base 1108, preferably thecentrally located push-up 1126 of the base 1108. Additionally oralternatively, the panel 1124 may include an initiator portion that isconfigured to initiate or cause the rest of the panel to move betweenthe outwardly and inwardly inclined positions. The initiator portion mayreduce or obviate the need for a pusher, providing for movement of thepanel 1124 due to the forces generated by the pressure differentialbetween the inside and outside of the container. To this end, theinitiator portion may have a lower angle of inclination than otherportions of the panel 1124 relative to the standing plane formed by thestanding ring 1118.

According to preferred embodiments, opposing vacuum panels 1116 aresubjected to vacuum force prior to repositioning of the base. Morepreferably, the vacuum panels 1116 move inwards prior to movement of thesecond wall 30 or panel 1124 to the inwardly inclined position. Othermethods of using containers as described herein can also be used withthe container of FIGS. 13-15.

It will be noted that the instep or first wall 1120 is configured so asto elevate the panel 1124 and other portions of the base 1108 above thestanding ring 1118 when the panel 1124 is outwardly inclined. Such aconfiguration provides improved container stability during the fillingoperations. However, the instep or first wall 1120 may be recessed to alesser extent such that a portion of the base extends below the standingring 1118 when the panel 1124 is outwardly inclined. As will beappreciated, this will mean that different portions of the containerbase 1108 act as the standing ring depending on whether the panel orsecond wall 1124 is inwardly or outwardly inclined.

The container shown in FIGS. 13 to 15 may also be used in pasteurisationprocesses. According to an example such process, the container is filledwith the panel 1116, 1124 in the inward position and then sealed. Thecontainer and its contents are then heated, causing an increase ininternal pressure. As a result of this the panels 1116, 1124 move to anoutward position. After the heating stage of the pasteurisation processis completed and the container is cooled, the panels 1116, 1124preferably revert to the inwardly inclined position.

According to preferred embodiments, different stages of the fillingand/or pasteurisation processes may be performed at different stationswithin a filling or processing facility. To this end, the container maybe conveyed in between stages or during a particular stage depending onsystem requirements and preferences.

FIGS. 16 and 17 show a container according to another embodiment. Manyof the features of this embodiment are the same or substantially thesame as those of the embodiment of FIGS. 13 to 15 and like referenceshave been used to aid clarity. Only features that differ from theembodiment of FIGS. 13 to 15 will be described.

As shown in FIGS. 16 and 17, the container of this embodiment includesfirst and second panels 1116 on two opposing faces of the sidewallthereof, at least one of which is a vacuum panel.

FIGS. 18 and 19 show another embodiment of a container that issubstantially identical to the container of FIGS. 16 and 17 and againonly points of difference will be described.

Notably, in the embodiment of FIGS. 18 and 19, the first wall or instep1120 is inclined at a lesser angle than in the embodiment of FIGS. 16and 17. As will be appreciated, other angles of inclination may also beused.

The operation or preferred use of the containers of FIGS. 16 and 17, andFIGS. 18 and 19, is substantially identical to that described inrelation to the embodiment of FIGS. 13 to 15.

Referring to FIGS. 11A-11E, an exemplary method of processing a plasticcontainer according to the present invention is shown. Prior toprocessing, the container 10 may be formed (e.g., blow molded) with thepressure panel 26 in the inwardly-inclined position. According to thisembodiment, a force can be applied to the pressure panel 26 in order tomove the pressure panel 26 into the outwardly-inclined position. Forexample, as shown in FIGS. 11A and 11B, a first mechanical pusher 50 canbe introduced through the opening in the container finish 14 and forceddownwardly on the pressure panel 26 in order to move it to theoutwardly-inclined position (shown in FIG. 11C). One of ordinary skillin the art will know that other types of mechanical or other forces canalternatively be used to move the pressure panel 26 into theoutwardly-inclined position. Alternatively, the container 10 can beinitially formed with the pressure panel 26 located in theoutwardly-inclined position.

Referring to FIG. 11C, the container 10 can be filled with liquidcontents when the pressure panel 26 is located in the outwardly-inclinedposition. Particularly, the container 10 can be “hot-filled” with theliquid contents at an elevated temperature, for example, 185 degrees C.As shown in FIG. 11C, the liquid contents can be introduced into thecontainer 10 via a filling nozzle 52 inserted through the opening in thecontainer finish 10, although one of ordinary skill in the art will knowthat any number of known filling devices and techniques can beimplemented. According to an alternative embodiment, the firstmechanical pusher 50 and the filling nozzle 52 can be the sameinstrument.

Referring to FIG. 11D, once the container 10 has been filled to thedesired level, the filling nozzle 52 can be removed, and a cap 54 can beapplied to the container finish 14. Any number of capping techniques anddevices known in the art can be used to apply the cap 54 to thecontainer finish 14. Next the container 10 can be cooled, for example,by spraying the container 10 with cool water, or alternatively, byleaving the container 10 in ambient conditions for a sufficient amountof time. As the container 10 and its contents cool, the contents tend tocontract. This volumetric change inside the sealed container 10 cancreate a vacuum force within the container 10.

In order to alleviate all or a portion of the vacuum forces within thecontainer 10, the pressure panel 26 can be moved from theoutwardly-inclined position of FIG. 11D to the inwardly-inclinedposition of FIG. 11E. For example, following filling, capping, andcooling of the container 10, an external force can be applied to thepressure panel 26, for example, by a second mechanical pusher 56, asshown in FIG. 11D. Alternatively, the pressure panel 26 can be moved bythe creation of relative movement of the container 10 relative to apunch or similar apparatus, in order to force the pressure panel 26 intothe inwardly-inclined position. Alternatively, the pressure panel 26 caninvert to the inwardly-inclined position under the internal vacuumforces within the sealed container 10. For example, all or a portion ofthe pressure panel 26 (e.g., the initiator portion) can be made flexibleenough to cause the pressure panel 26 to invert under the internalvacuum forces.

The inversion of the pressure panel 26 from the outwardly-inclinedposition to the inwardly-inclined position reduces the internal volumeof the container 10, and thereby increases the pressure inside thesealed container 10. This can alleviate any vacuum created within thecontainer 10 due to the hot-fill process. This can also remedy anydeformation of the container 10 that was caused as a result of theinternal vacuum.

As shown in FIGS. 11A-E, the entire pressure panel 26 is above the planeP of the standing surface 21 (see FIG. 11C) of the container 10. As aresult of this configuration, the containers 10 according to the presentinvention can be stored, transported, and capped/filled, etc., all whilestanding on the standing surface 21. This can eliminate the need for anyadapters or other devices to stabilize the container 10 in the uprightposition. This can also make the containers 10 of the present inventionmore readily adapted for use with conventional, existing containertransports, capping and filling stations, and storage facilities.

Referring to FIGS. 12A-C, an exemplary method of blow molding a 15plastic container according to the present invention is shown. Referringto FIG. 12A, the method includes enclosing a softened polymer material(such as PET, PEN, PP, blends thereof, and other suitable materialsknown in the art) within a blow mold. In the exemplary embodiment shown,the polymer material comprises a plastic container preform 60. However,according to an alternative embodiment, the polymer material cancomprise a tube of extruded polymer material, for example, as used inthe known process of “extrusion blow molding.”

The blow mold can comprise two or more side mold portions 62, 64, and abase mold portion 66. The side mold portions 62, 64 can move from anopen position (not shown) in which the side mold portions are separatedfrom one another, to a closed position, shown in FIGS. 12A-C. In theclosed position, shown, the side mold portions 62, 64 define a moldcavity 68 having an open bottom. The mold cavity 68 corresponds to theshape of a plastic container to be molded therein. The base mold portion66 is located in the open bottom region of the mold cavity 68 and ismovable with respect to the side mold portions 62, 64 in the verticaldirection (as viewed in FIGS. 12A-C) between the retracted positionshown in FIGS. 12A and 12B, and the extended position shown in FIG. 12C.Mechanical, pneumatic, hydraulic, or other means known in the art can beimplemented to move the base mold portion 66 between the retracted andextended positions.

A stretch rod 70 can be inserted into the neck portion of the softenedpreform 60, and can be used to stretch or elongate the preform 60. Airor another medium can be expelled from the stretch rod 70 or otherdevice to at least partially inflate the preform 60 into conformity withthe mold cavity 68 in what is commonly known in the art of stretch blowmolding as a “pre-blow” step. Preferably, the preform 60 is inflatedinto substantially complete conformity with the mold cavity 68 while thebase mold portion 66 is in the retracted position, as shown in FIG. 12B.In order to stretch blow mold the container from the partially inflatedvolume, it is commonly known in the art of stretch blow molding toincrease the pressure during the final blowing step in order to forcethe plastic material into complete conformity with the mold cavity 68.This can eliminate the need for the polymer material to expand deeplyinto tight corners, narrow spaces, etc., that are associated with thedeeply-set pressure panel of the present invention. This can avoidresultant thin or weak spots in the formed container.

While the polymer material is still in a softened state, the base moldportion 66 can be displaced upwardly into the mold cavity 68 to form atransverse pressure panel deeply set within the base portion of theplastic container (see, for example, the base 20 and pressure panel 26of FIGS. 1-4). Air can continue to be expelled to blowing pressure intothe stretch rod in the blow mold cavity during displacement of the basemold portion 66 to the extended position, or alternatively, the supplyof air can be turned off. Referring to FIGS. 1-4, by “deeply set” it ismeant that the pressure panel 26 is located entirely between thestanding plane P and the upper portion 12 of the container when thepressure panel 26 is in the outwardly-inclined position (FIG. 2) andwhen it is in the inwardly-inclined position (FIG. 3). In the exemplaryembodiment of FIGS. 12A-C, the base mold portion 66 moves substantiallyalong the longitudinal axis of the plastic container being formed in themold cavity 68, however, other orientations are possible.

Once the plastic container has been formed in the mold cavity 68, thebase mold portion 66 can return to the retracted position, and the sidemold portions 62, 64 can separate to release the formed container.

By utilizing the blow molding method of the present invention, it ispossible to initially form the general container shape with a generallyflat bottom portion, and then deflect the bottom upwardly at orientationtemperature. As a result, the container base and deeply-set pressurepanel can be of improved material thickness and uniformity. In addition,the base and pressure panel can be multi-axially stretch oriented toprovide increased strength without the attendant thinness or weakness atthe heel portion of the bottle.

The base of the plastic container according to the present invention ispreferably crystallized to some extent. Some degree of crystallinityand/or biaxial orientation can be achieved normally during the blowmolding process. However, crystallization can be promoted through heatsetting of the container. For example, the walls and base of the moldcan be held at an elevated temperature to promote crystallization. Whenthe container is heat set at a temperature of about 180 degrees F., thecontainer sidewalls, base, pressure panel, etc., can be typicallycrystallized to about 20%. This degree of crystallinity is typical for ablow molding process and does not represent a significant amount of heatsetting or increased crystallinity or orientation, as compared with atypically prepared container. However, the properties of the base andpressure panel of the present invention can be advantageously enhancedby heat setting the container, and particularly the base and pressurepanel, at ever higher temperatures. Such temperatures can be, forexample, greater than 250 degrees F. and can be 325 degrees F. or evenhigher. When these elevated heat set temperatures are utilized,crystallinity can be increased to greater than 20% or 25% or more. Onedrawback of increasing crystallinity and biaxial orientation in aplastic container is that this process introduces opacity into thenormally clear material. However, unlike bases in prior art containers,which can require a crystallinity of 30% or more, utilizingcrystallinities of as low as 22-25% with a base structure according tothe present invention can achieve significant structural integrity,while maintaining the substantial clarity of a base that is preferred bymanufacturers, packagers and consumers.

U.S. Pat. Nos. 4,465,199; 3,949,033; 4,378,328; and 5,004,109, all ofwhich are incorporated herein by reference, disclose further detailsrelating to blow molding methods utilizing displaceable mold portions.The methods disclosed in these references can also be implemented toform plastic 5 containers according to the present invention. Accordingto an alternative embodiment of the invention, the plastic container canbe removed from the blow mold prior to forming the deeply-set pressurepanel. Outside of the mold, the pressure-panel and related structure(s)can be formed in the base of the plastic container using a mandrel orsimilar device. U.S. Pat. No. 4,117,062, the entire content of which isincorporated herein by reference, provides further details on this typeof post-mold processing.

The embodiments illustrated and discussed in this specification areintended only to teach those skilled in the art the best way known tothe inventors to make and use the invention. Nothing in thisspecification should be considered as limiting the scope of the presentinvention. All examples presented are representative and non-limiting.The above-described embodiments of the invention may be modified orvaried, without departing from the invention, as appreciated by thoseskilled in the art in light of the above teachings. It is therefore tobe understood that, within the scope of the claims and theirequivalents, the invention may be practiced otherwise than asspecifically described.

1. A method for handling a hot-filled plastic container having a longitudinal axis, the container comprising: a finish; a sidewall portion extending from the finish and comprising a plurality of ribs; a base portion extending from the sidewall portion such that the finish, the sidewall portion and the base portion define an interior volume therein for retaining a liquid commodity, the base portion having a plurality of footed or support portions having a downwardly inclined outer annular wall portion to form a discontinuous or footed contact surface for supporting the container; the base portion further including an inner annular wall, a central push-up portion recessed along the longitudinal axis toward the finish, and a plurality of webs extending radially along the base portion in the transverse direction or along a transverse axis substantially perpendicular to the longitudinal axis, each one of the webs having a surface that is radially displaced between the footed or support portions and longitudinally displaced upwardly from the footed contact surface; wherein prior to filling and sealing: the outer annular wall is configured to extend downwardly away from the finish to the footed contact surface, and the inner annular wall is configured to extend inwardly along the transverse axis away from the footed contact surface to the push-up portion; and wherein after sealing: the inner annular wall and the push-up portion are configured to move upwardly closer to the finish to compensate for vacuum pressure created following a cooling of a heated liquid within the sealed container; the method comprising: hot-filling the plastic container with the inner annular wall and the push-up portion in a first position, wherein, in the first position, the inner annular wall extends above the footed contact surface of the base portion of the plastic container; sealing the hot-filled plastic container with the inner annular wall and push-up portion in the first position; conveying the hot-filled and sealed plastic container having the inner annular wall and push-up portion in the first position; and creating a vacuum pressure in the hot-filled and sealed plastic container by cooling and repositioning the inner annular wall and the push-up portion of the hot-filled and sealed plastic container under a mechanical force from the first position to a second position, wherein the central push-up portion or a portion of the inner annular wall moves or inverts upwardly toward the finish and one of the plurality of webs has an end adjacent to the sidewall portion, wherein the inner annular wall and push-up portion are positioned longitudinally away from the finish in the first position, and longitudinally toward the finish in the second position, to reduce at least a portion of the vacuum pressure, said repositioning being performed such that no part of the inner annular wall and the push-up portion extend below the footed contact surface of the base portion of the hot-filled and sealed plastic container.
 2. The method of claim 1, wherein the sidewall portion includes one or more vacuum panels and the vacuum panels move inwardly toward the longitudinal axis under vacuum force to remove a first portion of vacuum pressure, and the inner annular wall and the push-portion move upwardly toward the finish under the mechanical force to remove a second portion of vacuum pressure.
 3. The method of claim 1, wherein the sidewall portion includes one or more vacuum panels or grip portions.
 4. The method of claim 1, wherein the web surface of each one of the plurality of webs is at least partially inclined downwardly relative to the transverse axis and the footed contact surface.
 5. The method of claim 1, wherein the inner annular wall merges with at least one web portion and extends to the container sidewall portion to form a radius.
 6. The method of claim 5, wherein the radius changes when the inner annular wall or web portion moves from an outwardly or downwardly inclined position to an inwardly or upwardly inclined position.
 7. The method of claim 5, wherein the inner annular wall merges with the central push-up portion to form a second radius.
 8. The method of claim 7, wherein the second radius changes when the inner annular wall moves from an outwardly or downwardly inclined position to an inwardly or upwardly inclined position.
 9. A method for handling a hot-filled plastic container having a longitudinal axis and a horizontal or transverse axis perpendicular to the longitudinal axis, the container comprising: a finish; a sidewall portion extending from the finish and comprising a plurality of ribs; a base portion extending from the sidewall portion such that the finish, the sidewall portion and the base portion define an interior volume therein for retaining a liquid commodity, the base portion having a plurality of footed or support portions having a downwardly inclined outer annular wall portion to form a discontinuous or footed contact surface for supporting the container; the base portion further including an inner annular wall, a central push-up portion recessed along the longitudinal axis toward the finish, and a plurality of webs extending radially along the base portion in the transverse direction, each one of the webs having a surface that is radially displaced between the footed or support portions and longitudinally displaced upwardly from the footed contact surface; wherein prior to filling and sealing: the outer annular wall is configured to extend downwardly away from the finish to the footed contact surface, the inner annular wall is configured to extend downwardly away from the finish and inwardly away from the footed contact surface to the push-up portion; and wherein after sealing: the inner annular wall and the push-up portion are configured to move upwardly closer to the finish under vacuum pressure created following a cooling of a heated liquid within the sealed container; the method comprising: hot-filling the plastic container with the inner annular wall and the push-up portion in a first position, wherein, in the first position, the inner annular wall extends downwardly away from the finish and no part of the inner annular wall or push-up portion extend below the footed contact surface of the base portion of the plastic container; sealing the hot-filled plastic container with the inner annular wall and push-up portion in the first position; conveying the hot-filled and sealed plastic container having the inner annular wall and push-up portion in the first position; and after said conveying, creating a vacuum pressure in each of the hot-filled and sealed plastic container by cooling and repositioning the inner annular wall and the push-up portion of the plastic container under a mechanical force from the first position to a second position to reduce at least a portion of the vacuum pressure wherein the central push-up portion or a portion of the inner annular wall moves or inverts upwardly toward the finish and one of the plurality of webs has an end adjacent to the sidewall portion, said repositioning being performed such that no part of the inner annular wall and the push-up portion extend below the footed contact surface of the base portion of the hot-filled and sealed plastic container.
 10. The method of claim 9, wherein the container further comprises a plurality of transversely oriented annular recessed channels or rib members within the base portion, wherein at least one of the plurality of channels or rib members is arranged between two of the plurality of webs.
 11. The method of claim 9, wherein the inner annular wall merges with at least one web portion and extends to the container sidewall portion to form a first radius, and the inner annular wall merges with the central push-up portion to form a second radius, wherein the first or second radius changes when the inner annular wall moves from an outwardly or downwardly inclined position to an inwardly or upwardly inclined position.
 12. The method of claim 9, wherein the web surface is visible from a side of the container.
 13. The container of claim 9, wherein the inner annular wall comprises regions of lesser and greater angular set.
 14. A method for handling a hot-filled plastic container having a longitudinal axis and a horizontal or transverse axis perpendicular to the longitudinal axis, the container comprising: a finish; a sidewall portion extending from the finish and comprising a plurality of ribs; a base portion extending from the sidewall portion such that the finish, the sidewall portion and the base portion define an interior volume therein for retaining a liquid commodity, the base portion having a plurality of footed or support portions having a downwardly inclined outer annular wall portion to form a discontinuous or footed contact surface for supporting the container; the base portion further including an inner annular wall, a central push-up portion recessed along the longitudinal axis toward the finish, and a plurality of webs extending radially along the base portion away from the inner annular wall in the transverse direction, each one of the webs having a surface that is radially displaced between the footed or support portions and longitudinally displaced upwardly from the footed contact surface; wherein prior to filling and sealing: the outer annular wall is configured to extend downwardly away from the finish to the footed contact surface, the inner annular wall is configured to extend inwardly away from the footed contact surface to the push-up portion, the inner annular wall being configured to extend away from the finish to a lesser degree with respect to a standing plane of the plastic container than the outer annular wall; and wherein after sealing: the inner annular wall and the push-up portion are configured to move upwardly closer to the finish to compensate for vacuum pressure created following a cooling of a heated liquid within the sealed container and the central push up or a portion of the inner annular wall moves or inverts upwardly toward the finish under a mechanical force and one of the plurality of webs has an end adjacent to the sidewall portion; the method comprising: hot-filling the plastic container with the inner annular wall and the push portion a first position, wherein, in the first position, the inner annular wall extends downwardly away from the finish and above the footed contact surface of the base portion of the plastic container; sealing the hot-filled plastic container with the inner annular wall and push-up portion in the first position; conveying the hot-filled and sealed plastic container having the inner annular wall and push-up portion in the first position; creating a vacuum pressure in the hot-filled and sealed plastic container by cooling; and after said cooling, repositioning the inner annular wall and the push-up portion of the hot-filled and sealed plastic container from the first position to a second position to reduce at least a portion of the vacuum pressure, said repositioning being performed by a mechanical force and such that no part of the inner annular wall and the push-up portion extend below the contact surface of the base portion of the hot-filled and sealed plastic container.
 15. The method of claim 14, wherein the container further comprises a plurality of transversely oriented annular recessed channels or rib members within the base portion, wherein at least one of the plurality of channels or rib members is arranged between two of the plurality of webs.
 16. The method of claim 15, wherein the inner annular wall merges with at least one web portion and extends to the container sidewall portion to form a first radius, and the inner annular wall merges with the central push-up portion to form a second radius, wherein the first or second radius changes when the inner annular wall moves from an outwardly or downwardly inclined position to an inwardly or upwardly inclined position.
 17. The method of claim 14, wherein the inner annular wall comprises regions of lesser and greater angular set. 